Circuit assembly

ABSTRACT

A circuit assembly includes a first conductive member; a second conductive member; and a holding member that is insulating and holds the first conductive member and the second conductive member; wherein the first conductive member has a first exposed surface exposed from the holding member, the second conductive member has a second exposed surface exposed from the holding member, the holding member includes an insulating portion located between the first exposed surface and the second exposed surface, and a conductive film covers at least a part of the first exposed surface and at least a part of the second exposed surface, while extending over the insulating portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Japanese Patent Application No. JP2021-177058 filed on Oct. 29, 2021, the contents of which areincorporated herein.

TECHNICAL FIELD

The present disclosure relates to a circuit assembly.

BACKGROUND

Conventional circuit assemblies include a control substrate, a pluralityof power supply terminals that supply electric power to the controlsubstrate, and a plurality of busbars that are electrically connected tothe power supply terminals, and constitute an electric power circuit(see JP 2019-96769A, for example). As shown in FIG. 4 , terminals 91 ofa conventional circuit assembly 90 are electrically connected to busbars92 by welding.

JP 2019-96769A is an example of related art.

SUMMARY

In the conventional circuit assembly 90, the terminals 91 need to beprovided with hold-down surfaces 91 a in order to weld the terminals 91to the busbars 92. Therefore, the space for placing the terminals 91increases, resulting in a larger circuit assembly 90.

Therefore, it is an object of the present disclosure to reduce the sizeof a circuit assembly.

According to an aspect of the present disclosure, a circuit assemblyincludes a first conductive member; a second conductive member; and aholding member that is insulating and holds the first conductive memberand the second conductive member; wherein the first conductive memberhas a first exposed surface exposed from the holding member, the secondconductive member has a second exposed surface exposed from the holdingmember, the holding member includes an insulating portion locatedbetween the first exposed surface and the second exposed surface, and aconductive film covers at least a part of the first exposed surface andat least a part of the second exposed surface, while extending over theinsulating portion.

According to the present disclosure, it is possible to reduce the sizeof a circuit assembly.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a circuit assembly accordingto an embodiment;

FIG. 2 is a plan view illustrating the circuit assembly;

FIG. 3 is an enlarged plan view illustrating the vicinity of powersupply terminals;

FIG. 4 is a perspective view illustrating a conventional circuitassembly.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

First, embodiments of the present disclosure will be listed anddescribed.

A circuit assembly of the present disclosure includes: a firstconductive member; a second conductive member; and a holding member thatis insulating and holds the first conductive member and the secondconductive member; wherein the first conductive member has a firstexposed surface exposed from the holding member, the second conductivemember has a second exposed surface exposed from the holding member, theholding member includes an insulating portion located between the firstexposed surface and the second exposed surface, and a conductive filmcovers at least a part of the first exposed surface and at least a partof the second exposed surface, while extending over the insulatingportion.

According to this circuit assembly, since the first conductive memberand the second conductive member held by the holding member respectivelyhave the first exposed surface and the second exposed surface exposedfrom the holding member, and at least a part of the first exposedsurface and at least a part of the second exposed surface are covered bythe conductive film that extends over the insulating portion, the twoexposed surfaces can be electrically connected to each other by theconductive film. With this, there is no need of forming any hold-downsurface for welding on one of the first conductive member and the secondconductive member, and thus it is possible to downsize that exposedsurface. As a result, it is possible to reduce the size of a circuitassembly.

Preferably, parts of the first conductive member other than the firstexposed surface are buried in the holding member, and parts of thesecond conductive member other than the second exposed surface areburied in the holding member.

In this case, by performing, for example, insert molding to bury a partof the first conductive member and a part of the second conductivemember into the holding member, it is easy to form the first exposedsurface and the second exposed surface.

Preferably, the conductive film is a metal plating film.

In this case, it is easy to form the conductive film.

Preferably, the first conductive member has a cut-out portion that iscut out and surrounds the second exposed surface.

In this case, it is possible to suppress heat generation of the firstconductive member that may occur due to a high current, compared to acase where the first conductive member has a hole that surrounds thesecond exposed surface.

Preferably, the first exposed surface and the second exposed surface arecoplanar with a surface of the insulating portion that faces theconductive film.

In this case, it is possible to form the conductive films more easily.

The following will describe details of the embodiment of the presentdisclosure with reference to the drawings. Note that at least somefeatures of the embodiment described below may be combined with eachother as appropriate.

Circuit Assembly

FIG. 1 is a perspective view showing a circuit assembly 10 according tothe present embodiment. FIG. 2 is a plan view of the circuit assembly10. In the following description of the present embodiment, directionssuch as “up”, “down”, “right”, “left”, “front/forward”, and “rear” arebased on the directions indicated in FIG. 1 .

In FIGS. 1 and 2 , the circuit assembly 10 can be installed in variousdevices, and the circuit assembly 10 of the present embodiment isinstalled in a vehicle. More specifically, the circuit assembly 10 isassembled in an electrical junction box disposed at a midway position ofa wiring route connecting a not-shown first in-vehicle device and anot-shown second in-vehicle device. The circuit assembly 10 includes aplurality of conductive plates (first conductive members) 11, aplurality of power supply terminals (second conductive members) 12, aplurality of control terminals 13, a plurality of electronic components14, and a holding member 15. The plurality of conductive plates 11, theplurality of power supply terminals 12, and the plurality of controlterminals 13 constitute an electric power circuit of the circuitassembly 10.

The circuit assembly 10 of the present embodiment includes threeconductive plates 11. The number of conductive plates 11 and the numberof power supply terminals 12 are the same, and one conductive plate 11and one power supply terminal 12 are electrically connected to eachother in a one-to-one relationship. Also, the circuit assembly 10 of thepresent embodiment includes ten control terminals 13. The number ofcontrol terminals 13 and the number of electronic components 14 are thesame, and one control terminal 13 and one electronic component 14 areelectrically connected to each other in a one-to-one relationship. Notethat the numbers of conductive plates 11, power supply terminals 12,control terminals 13, and electronic components 14 are suitablyselected, and can be changed as appropriate.

The conductive plates 11 are manufactured by pressing a metal plate intoa predetermined shape, and are referred to also as “busbars”. Theconductive plates 11 are preferably copper members made of, for example,pure copper, a copper alloy, or the like. The entire conductive plates11 are conductors, and the conductive plates 11 do not have any wiringpatterns as formed on a typical printed board. The circuit assembly 10of the present embodiment includes, as the plurality of conductiveplates 11, a first conductive plate 111, a second conductive plate 112,and a third conductive plate 113.

The first conductive plate 111 is arranged at the frontmost position,and extends in a left-right direction. The second conductive plate 112is arranged behind the first conductive plate 111 at a distance thereto,and extends in the left-right direction. On both front and rear sides ofthe second conductive plate 112, a plurality of recesses 112 a areformed at intervals in the left-right direction (see also FIG. 3 ). Inthe present embodiment, on each of the front and rear sides of thesecond conductive plate 112, five recesses 112 a are formed.

The third conductive plate 113 includes a conductive body portion 113 athat extends in the left-right direction, and a conductive extensionportion 113 b that extends forward from a left end portion of theconductive body portion 113 a. The conductive body portion 113 a isarranged behind the second conductive plate 112 at a distance thereto. Afront portion of the conductive extension portion 113 b extends to aposition located on the left side of the first conductive plate 111. Theconductive extension portion 113 b is arranged on the left side of thefirst conductive plate 111 and the second conductive plate 112 at adistance thereto. Note that the shapes of the first conductive plate111, the second conductive plate 112, and the third conductive plate 113are not limited to the shapes employed in the present embodiment. Forexample, the third conductive plate 113 may be constituted only by theconductive body portion 113 a.

The power supply terminals 12 are manufactured by pressing a metal wirematerial into a predetermined shape. The power supply terminals 12 areterminals made of metal. The power supply terminals 12 are preferablycopper members made of, for example, pure copper, a copper alloy, or thelike. The power supply terminals 12 are electrically connected to theconductive plates 11 via later-described conductive films 20, and supplyelectric power to a not-shown control substrate from the conductiveplates 11.

The circuit assembly 10 of the present embodiment includes, as theplurality of power supply terminals 12, a first power supply terminal121, a second power supply terminal 122, and a third power supplyterminal 123. The first power supply terminal 121 is arranged on theleft side of the first conductive plate 111. The second power supplyterminal 122 is arranged on the left side of the second conductive plate112. The third power supply terminal 123 is arranged on the right sideof an extended conductive portion 113 b of the third conductive plate113.

The control terminals 13 are manufactured by pressing a metal wirematerial into a predetermined shape. The control terminals 13 areterminals made of metal. The control terminals 13 are preferably membersmade of copper such as, for example, pure copper, a copper alloy, or thelike. In the present embodiment, the plurality of control terminals 13are arranged in the recesses 112 a formed in the second conductive plate112 on the front and rear sides. The plurality of control terminals 13extend downward, and are electrically connected to the controlsubstrate.

The electronic components 14 are, for example, semiconductor relays suchas field effect transistors (FETs). The following describes a case wherethe electronic components 14 are field effect transistors, and the fieldeffect transistors are denoted as “FETs”. The plurality of FETs 14 areplaced on the first conductive plate 111 and the third conductive plate113 at intervals in the left-right direction.

Each of the FETs 14 includes a plurality of terminals. As shown in anenlarged portion in FIG. 2 , each FET 14 includes, as the plurality ofterminals, a plurality of (four in the illustration) source terminals 14a, one gate terminal 14 b, and one drain terminal 14 c (see also FIG. 3). The source terminals 14 a are electrically connected to the secondconductive plate 112 with solder or the like.

The gate terminal 14 b is electrically connected to the correspondingcontrol terminal 13 with solder or the like. The drain terminal 14 c iselectrically connected to the first conductive plate 111 or the thirdconductive plate 113 with solder or the like. Note that the electroniccomponents 14 may be components other than field effect transistors, andmay also be mechanical relays, for example.

The holding member 15 is made of a thermoplastic resin. The holdingmember 15 is made of, for example, PPS (polyphenylene sulfide), PBT(polybutylene terephthalate), nylon, PP (polypropylene), PE(polyethylene), or the like, and is insulating. The holding member 15 ofthe present embodiment is made of PPS. The holding member 15 is formedby injection molding. In the present embodiment, the holding member 15is manufactured by insert molding performed with the conductive plates11, the power supply terminals 12, and the control terminals 13 placedin an injection molding die (not shown). With this, the holding member15 holds the conductive plates 11, the power supply terminals 12, andthe control terminals 13. The conductive plates 11, the power supplyterminals 12, the control terminals 13, and the holding member 15 serveas an insert-molded article formed in one piece.

Exposed Surface

The conductive plates 11 each have an exposed surface (first exposedsurface) that is exposed from the holding member 15. Specifically, thefirst conductive plate 111 has an exposed surface 111 b that is exposedfrom the holding member 15 to the upper side. The parts (located belowthe exposed surface 111 b) of the first conductive plate 111 other thanthe exposed surface 111 b are buried in the holding member 15. Apredetermined number of (five in the illustration) FETs 14 are placed onthe exposed surface 111 b. The second conductive plate 112 has anexposed surface 112 c that is exposed from the holding member 15 to theupper side. The parts (located below the exposed surface 112 c) of thesecond conductive plate 112 other than the exposed surface 112 c areburied in the holding member 15.

The third conductive plate 113 includes an exposed surface 113 d that isexposed from the holding member 15 to the upper side. The exposedsurface 113 d includes a main exposed surface 113 e in the conductivebody portion 113 a that is exposed from the holding member 15, and anextended exposed surface 113 f in the conductive extension portion 113 bthat is exposed from the holding member 15. The parts (located below theexposed surface 113 d) of the third conductive plate 113 other than theexposed surface 113 d are buried in the holding member 15. Apredetermined number of (five in the illustration) remaining FETs 14 areplaced on the exposed surface 113 d.

FIG. 3 is an enlarged plan view showing the vicinity of the power supplyterminals 12. In FIG. 3 , each of the power supply terminals 12 has anexposed surface (second exposed surface) exposed from the holding member15. Specifically, the first power supply terminal 121 has an exposedsurface 121 a exposed from the holding member 15 to the upper side. Thesecond power supply terminal 122 has an exposed surface 122 a exposedfrom the holding member 15 to the upper side. The third power supplyterminal 123 has an exposed surface 123 a exposed from the holdingmember 15 to the upper side. The parts (located below the exposedsurfaces 121 a, 122 a, and 123 a) of the power supply terminals 121,122, and 123 other than the exposed surfaces 121 a, 122 a, and 123 a areburied in the holding member 15.

Cut-Out Portion

A cut-out portion 111 a is formed in a left end portion of the firstconductive plate 111, surrounding the exposed surface 121 a of the firstpower supply terminal 121. The cut-out portion 111 a of the presentembodiment is recess-shaped, opening to the left side thereof. A cut-outportion 112 b is formed in the corner on the rear left side of thesecond conductive plate 112, surrounding the exposed surface 122 a ofthe second power supply terminal 122. The cut-out portion 112 b of thepresent embodiment is cut out in an L-shape, opening to the rear andleft sides. A cut-out portion 113 c is formed in a right end portion ofthe extended conductive portion 113 b of the third conductive plate 113,surrounding the exposed surface 123 a of the third power supply terminal123. The cut-out portion 113 c of the present embodiment is formedrecess-shaped, opening to the right side.

Insulating Portions

In FIGS. 2 and 3 , the holding member 15 includes, as insulatingportions that insulate the exposed surfaces of adjacent conductiveplates 11 from each other, a first insulating portion 15 a, a secondinsulating portion 15 b, and a third insulating portion 15 c. The firstinsulating portion 15 a is located between the exposed surface 111 b ofthe first conductive plate 111 and the exposed surface 112 c of thesecond conductive plate 112, and insulates the exposed surfaces 111 band 112 c from each other. The second insulating portion 15 b is locatedbetween the exposed surface 112 c of the second conductive plate 112 andthe main exposed surface 113 e of the third conductive plate 113, andinsulates the exposed surfaces 112 c and 113 e from each other.

The third insulating portion 15 c is located between the extendedexposed surface 113 f of the third conductive plate 113, and the exposedsurfaces 111 b and 112 c of the first conductive plate 111 and thesecond conductive plate 112, and insulates the extended exposed surface113 f, and the exposed surfaces 111 b and 112 c from each other. Thethird insulating portion 15 c is coupled to the left ends of the firstinsulating portion 15 a and the second insulating portion 15 b.

In FIG. 3 , the holding member 15 includes, as insulating portions thatinsulate the conductive plates 11 and the exposed surfaces of the powersupply terminals 12 from each other, a fourth insulating portion 15 d, afifth insulating portion 15 e, and a sixth insulating portion 15 f.

The fourth insulating portion 15 d is located between the exposedsurface 111 b of the first conductive plate 111 and the exposed surface121 a of the first power supply terminal 121, and insulates the twoexposed surfaces 111 b and 121 a from each other. The fourth insulatingportion 15 d of the present embodiment is formed in the cut-out portion111 a of the first conductive plate 111, while being adjacent to thefront, right, and rear sides of the exposed surface 121 a of the firstpower supply terminal 121. The fourth insulating portion 15 d is coupledto the third insulating portion 15 c.

The fifth insulating portion 15 e is located between the exposed surface112 c of the second conductive plate 112 and the exposed surface 122 aof the second power supply terminal 122, and insulates the two exposedsurfaces 112 c and 122 a from each other. The fifth insulating portion15 e of the present embodiment is formed in the cut-out portion 112 b ofthe second conductive plate 112, while being adjacent to the front andright sides of the exposed surface 122 a of the second power supplyterminal 122. The fifth insulating portion 15 e is coupled to the secondinsulating portion 15 b and the third insulating portion 15 c.

The sixth insulating portion 15 f is located between the extendedexposed surface 113 f of the third conductive plate 113 and the exposedsurface 123 a of the third power supply terminal 123, and insulates thetwo exposed surfaces 113 f and 123 a from each other. The sixthinsulating portion 15 f of the present embodiment is formed in thecut-out portion 113 c of the third conductive plate 113, while beingadjacent to the front, left, and rear sides of the exposed surface 123 aof the third power supply terminal 123. The sixth insulating portion 15f is coupled to the third insulating portion 15 c.

The upper surfaces of the first to third insulating portions 15 a to 15c, and the upper surfaces of the fourth to sixth insulating portions 15d to 15 f (the upper surfaces that face the later-described conductivefilms 20) are coplanar. Furthermore, the exposed surfaces 111 b, 112 c,and 113 d of the conductive plates 11, and the exposed surfaces 121 a,122 a, and 123 a of the power supply terminals 12 are coplanar with theupper surfaces of the insulating portions 15 a to 15 f of the holdingmember 15 (see also FIG. 1 ).

Conductive Films

The circuit assembly 10 includes a plurality of conductive films 20 thatelectrically connect the conductive plates 11 to the power supplyterminals 12. The conductive films 20 are deposited by vacuum vapordeposition, for example. The conductive films 20 of the presentembodiment are metal plating films in which a nickel plating layer islaminated on a copper plating layer. The circuit assembly 10 of thepresent embodiment includes, as the plurality of conductive films 20, afirst conductive film 21, a second conductive film 22, and a thirdconductive film 23.

The first conductive film 21 electrically connects the first conductiveplate 111 and the first power supply terminal 121. Specifically, thefirst conductive film 21 covers a part (left end portion) of the exposedsurface 111 b of the first conductive plate 111 and a part (front endportion) of the exposed surface 121 a of the first power supply terminal121 while extending over the fourth insulating portion 15 d.

The second conductive film 22 electrically connects the secondconductive plate 112 and the second power supply terminal 122.Specifically, the second conductive film 22 covers a part (left endportion) of the exposed surface 112 c of the second conductive plate 112and a part (front end portion) of the exposed surface 122 a of thesecond power supply terminal 122 while extending over the fifthinsulating portion 15 e.

The third conductive film 23 electrically connects the third conductiveplate 113 and third power supply terminal 123. Specifically, the thirdconductive film 23 covers a part (right end portion) of the extendedexposed surface 113 f of the third conductive plate 113, and a part(left end portion) of the exposed surface 123 a of the third powersupply terminal 123, while extending over the sixth insulating portion15 f.

Effects

According to the circuit assembly 10 of the present embodiment, theexposed surfaces 111 b, 112 c, and 113 d of the conductive plates 11exposed from the holding member 15 and the exposed surfaces 121 a, 122a, and 123 a of the power supply terminals 12 exposed from the holdingmember 15 are covered by the conductive films 20 that extends over theinsulating portions 15 d, 15 e, and 15 f, and thus the conductive plates11 and the power supply terminals 12 are electrically connected by theconductive films 20. With this, there is no need of forming anyhold-down surface for welding on the power supply terminal 12, making itpossible to downsize the exposed surfaces 121 a, 122 a, and 123 a of thepower supply terminals 12. As a result, it is possible to reduce thesize of the circuit assembly 10.

By insert molding, parts of the conductive plates 11 other than theexposed surfaces 111 b, 112 c, and 113 d are buried in the holdingmember 15, and parts of the power supply terminals 12 other than theexposed surfaces 121 a, 122 a, and 123 a are buried in the holdingmember 15. With this, the exposed surfaces 111 b, 112 c, and 113 d ofthe conductive plates 11, and the exposed surfaces 121 a, 122 a, and 123a of the power supply terminals 12 can be formed easily.

The cut-out portions 111 a, 112 b, and 113 c are respectively formed inthe conductive plates 11, surrounding the exposed surfaces 121 a, 122 a,and 123 a of the power supply terminals 12. Accordingly, it is possibleto suppress heat generation of the conductive plates 11 that may occurdue to a high current, compared to a case where the conductive plates 11have holes that surround the respective power supply terminal 12.

Since the conductive films 20 are metal plating films, it is easy toform the conductive films 20. Also, by using metal plating films as theconductive films 20, it is also possible to mount another electroniccomponent on the conductive films 20.

Since the exposed surfaces 111 b, 112 c, and 113 d of the conductiveplates 11, the exposed surfaces 121 a, 122 a, and 123 a of the powersupply terminals 12, and the upper surfaces of the insulating portions15 d, 15 e, and 15 f are coplanar, it is easy to form the conductivefilms 20.

Other Considerations

Although the conductive films 20 of the present embodiment cover partsof the exposed surfaces (first exposed surfaces) 111 b, 112 c, and 113 dof the conductive plates 11, the conductive films 20 may also cover theentire exposed surfaces 111 b, 112 c, and 113 d. Also, although theconductive films 20 cover parts of the exposed surfaces (second exposedsurfaces) 121 a, 122 a, and 123 a of the power supply terminals 12, theconductive films 20 may also cover the entire exposed surfaces 121 a,122 a, and 123 a. The conductive films 20 of the present embodiment aredeposited by vacuum vapor deposition. But the present disclosure is notlimited to this, and the conductive films 20 may also be deposited by,for example, sputtering, printing, or the like.

The embodiments disclosed herein are to be construed as being exemplaryand non-limiting in all respects. The scope of the present disclosure isnot defined by the description above but is defined by the claims, andall modifications within the meaning and scope equivalent to the claimsare intended to be included.

What is claimed is:
 1. A circuit assembly comprising: a first conductivemember; a second conductive member; and a holding member that isinsulating and holds the first conductive member and the secondconductive member; wherein the first conductive member has a firstexposed surface exposed from the holding member, the second conductivemember has a second exposed surface exposed from the holding member, theholding member includes an insulating portion located between the firstexposed surface and the second exposed surface, and a conductive filmcovers at least a part of the first exposed surface and at least a partof the second exposed surface, while extending over the insulatingportion.
 2. The circuit assembly according to claim 1, wherein parts ofthe first conductive member other than the first exposed surface areburied in the holding member, and parts of the second conductive memberother than the second exposed surface are buried in the holding member.3. The circuit assembly according to claim 1, wherein the conductivefilm is a metal plating film.
 4. The circuit assembly according to claim1, wherein the first conductive member has a cut-out portion that is cutout and surrounds the second exposed surface.
 5. The circuit assemblyaccording to claim 1, wherein the first exposed surface and the secondexposed surface are coplanar with a surface of the insulating portionthat faces the conductive film.
 6. The circuit assembly according toclaim 2, wherein the conductive film is a metal plating film.
 7. Thecircuit assembly according to claim 2, wherein the first conductivemember has a cut-out portion that is cut out and surrounds the secondexposed surface.
 8. The circuit assembly according to claim 3, whereinthe first conductive member has a cut-out portion that is cut out andsurrounds the second exposed surface.
 9. The circuit assembly accordingto claim 2, wherein the first exposed surface and the second exposedsurface are coplanar with a surface of the insulating portion that facesthe conductive film.
 10. The circuit assembly according to claim 3,wherein the first exposed surface and the second exposed surface arecoplanar with a surface of the insulating portion that faces theconductive film.
 11. The circuit assembly according to claim 4, whereinthe first exposed surface and the second exposed surface are coplanarwith a surface of the insulating portion that faces the conductive film.